INVESTIGATION OF BEHAVIOR PATTERN AND RISK-ASSESSMENT OF MAIN INDOOR AIR POLLUTANTS IN SAPPORO AND NAGOYA CITY PART 2: NATURAL RADIOACTIVE SUBSTANCE

Radon short-lived decay products generated from the earth is one of the serious indoor air pollutantsin Europe and US. We measured natural radioactive substance and main indoor air pollutants in thefacilities of Sapporo and Nagoya City. The main measured items were composed of 1) air temperature,2) air humidity, 3) CO2, 4) CO, 5) HCHO, 6) VOCs, 7) airborne fungi,8) airborne bacteria, 9) SPM and10) Rn and Rn-Dts. The subjected spaces were laboratories, lecture rooms, libraries, museums, publicunderground spaces, closed spaces without window and outdoors. In several facilities radonconcentration was very high. We set up boxy measuring devices in the campus of Hokkaido University.By using the filter pack method we measured concentration of radon and its decay products inside ofthe boxy measuring device and the surrounding outdoor air. We also performed to measure ventilationrate of the device. By using the ventilation rate and concentration values radon exhalation rate wascalculated. We found out that radon exhalation rate might be significantly related with atmospherepressure. We measured the amount of Rn of the soil and Rn concentration level at the vacant space inthe ground of Sapporo. In order to predict the deposition rate to respiration organ, we measured particlesize distribution of radioactive aerosol. In the all facilities in Nagoya and Sapporo City, its single-peakedpattern was shown. By using data of particle size distribution of radioactive aerosol deposition rates ofparticle in respiratory organs were calculated. The calculated results showed that the deposition rate inalveolus and alveolar duct might be extremely high.